Developing an Effective and Robust Process for Manufacturing Bipolar SiC Power Devices

2007 ◽  
Vol 556-557 ◽  
pp. 77-80 ◽  
Author(s):  
Joseph J. Sumakeris ◽  
Brett A. Hull ◽  
Michael J. O'Loughlin ◽  
Marek Skowronski ◽  
Vijay Balakrishna
Keyword(s):  
Process Optimization ◽  
Basal Plane ◽  
Smooth Surface ◽  
Defect Density ◽  
Comprehensive Approach ◽  
Power Devices ◽  
Extended Defect ◽  
Basal Plane Dislocation ◽  
Robust Process

We detail a comprehensive approach to preparing epiwafers for bipolar SiC power devices which entails etching the substrate, growing a semi-sacrificial basal plane dislocation (BPD) conversion epilayer, polishing away a portion of that conversion epilayer to recover a smooth surface and then growing the device epilayers following specific methods to prevent the reintroduction of BPDs. With our best processing, we achieve a BPD density of < 10 cm-2 and an extended defect density of < 1.5 cm-2. Specifics of low BPD processing and particular concerns and metrics will be discussed in regard to process optimization and simplification.

Development of Epitaxial SiC Processes Suitable for Bipolar Power Devices

2005 ◽  
Vol 483-485 ◽  
pp. 155-158 ◽  
Author(s):  
Joseph J. Sumakeris ◽  
Mrinal K. Das ◽  
Seo Young Ha ◽  
Edward Hurt ◽  
Kenneth G. Irvine ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
Growth Process ◽  
Defect Density ◽  
Power Devices ◽  
Extended Defect ◽  
Bipolar Devices ◽  
Significant Barrier ◽  
The Stability ◽  
Vf Drift ◽  
Growth Technology

We present a survey of the most important factors relating to an epitaxial SiC growth process that is suitable for bipolar power devices. During the last several years, we have advanced our hot-wall SiC epitaxial growth technology to the point that we can support the transition of bipolar power devices from demonstrations to applications. Two major concerns in developing a suitable epitaxial technology are epilayer uniformity and extended defect density. Our state-of-theart capability permits the realization of 1-cm2 area devices with exceptional yields. Another major concern is the stability of bipolar devices during forward conduction. We have developed proprietary substrate and epilayer preparation technologies that have essentially eliminated Vf drift as a significant barrier to the exploitation of SiC based bipolar devices.

Basal Plane Dislocation Free Recombination Layers on Low-Doped Buffer Layer for Power Devices

2017 ◽  
Vol 17 (4) ◽  
pp. 1550-1557 ◽  
Author(s):  
Anusha Balachandran ◽  
T. S. Sudarshan ◽  
M. V. S. Chandrashekhar
Keyword(s):  
Buffer Layer ◽  
Basal Plane ◽  
Power Devices ◽  
Basal Plane Dislocation

Epitaxial Growth on 2° Off-axis 4H SiC Substrates with Addition of HCl

2008 ◽  
Vol 1069 ◽  
Author(s):  
Jie Zhang ◽  
Swapna Sunkari ◽  
Janice Mazzola ◽  
Becky Tyrrell ◽  
Gray Stewart ◽  
...  
Keyword(s):  
Growth Rate ◽  
Dislocation Density ◽  
Epitaxial Growth ◽  
Basal Plane ◽  
Defect Density ◽  
Mapping Technique ◽  
Standard Process ◽  
Basal Plane Dislocation ◽  
Non Destructive ◽  
Koh Etching

ABSTRACTEpitaxial growth on 3-in, 2° off-axis 4H SiC substrates has been conducted in a horizontal hot-wall CVD reactor with HCl addition. The thickness of the epiwafers ranges from 3&#61549;m to 11 &#61549;m and the growth rate is 7 − 7.5 &#61549;m/h. Although a rougher surface and a higher triangular defect density is observed using the standard process for 4° growth, an improved process has resulted in reduced triangular defect density down to around 4 cm−2 and a smoother surface with the roughness of 1.1 nm for a 3.7 &#61549;m thick epiwafer. Most interestingly, the basal plane dislocation density in the 2° off-axis epiwafers has been reduced to "negligible" levels, as confirmed by both the non-destructive UVPL mapping technique and the molten KOH etching on 2° epiwafers with thickness of around 10 &#61549;m.

Status of 4H-SiC Substrate and Epitaxial Materials for Commercial Power Applications

2004 ◽  
Vol 815 ◽  
Author(s):  
A.R. Powell ◽  
J.J. Sumakeris ◽  
R.T. Leonard ◽  
M.F. Brady ◽  
St.G. Müller ◽  
...  
Keyword(s):  
Basal Plane ◽  
Stacking Faults ◽  
Epitaxial Layers ◽  
Power Devices ◽  
Pin Diodes ◽  
Dislocation Densities ◽  
The Status ◽  
Basal Plane Dislocation ◽  
Current Production ◽  
Schottky Device

AbstractThe performance enhancements offered by the next generation of SiC high power devices offer potential for enormous growth in SiC power device markets in the next few years. For this growth to occur, it is imperative that substrate and epitaxial material quality increases to meet the needs of the targeted applications. We will discuss the status and requirements for SiC substrates and epitaxial material for power devices such as Schottky and PiN diodes. For the SiC Schottky device where current production is approaching 50 amp devices, there are several material aspects that are key. These include; wafer diameter (3-inch and 100-mm), micropipe density (<0.3 cm−2 for 3-inch substrates and 16 cm−2 for 100-mm substrates), epitaxial defect densities (total electrically active defects <1.5 cm−2), epitaxial doping and epitaxial thickness uniformity. For the PiN diodes the major challenge is the degradation of the Vf characteristics due to the introduction of stacking faults during the device operation. We have demonstrated that the stacking faults are often generated from basal plane dislocations in the active region of the device. Additionally we have demonstrated that by reducing the basal plane dislocation density, stable PiN diodes can be produced. At present typical basal plane dislocation densities in our epitaxial layers are 100 to 500 cm−2; however, we have achieved basal plane dislocation densities as low as 4 cm−2 in epitaxial layers grown on 8° off-axis 4H-SiC substrates.

Silicon Carbide Hot-Wall Epitaxy for Large-Area, High-Voltage Devices

2008 ◽  
Vol 1069 ◽  
Author(s):  
Michael O'Loughlin ◽  
K. G. Irvine ◽  
J. J. Sumakeris ◽  
M. H. Armentrout ◽  
B. A. Hull ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Process Optimization ◽  
High Voltage ◽  
Defect Density ◽  
Epitaxial Layers ◽  
Power Devices ◽  
Large Area ◽  
Device Processing ◽  
Defect Densities ◽  
Hot Wall Epitaxy

ABSTRACTThe growth of thick silicon carbide (SiC) epitaxial layers for large-area, high-power devices is described. Horizontal hot-wall epitaxial reactors with a capacity of three, 3-inch wafers have been employed to grow over 350 epitaxial layers greater than 100 μm thick. Using this style reactor, very good doping and thickness uniformity and run-to-run reproducibility have been demonstrated. Through a combination of reactor design and process optimization we have been able to achieve the routine production of thick epitaxial layers with morphological defect densities of around 1 cm−2. The low defect density epitaxial layers in synergy with improved substrates and SiC device processing have resulted in the production of 10 A, 10 kV junction barrier Schottky (JBS) diodes with good yield (61.3%).

4H-SiC Epitaxy with Very Smooth Surface and Low Basal Plane Dislocation on 4 Degree Off-Axis Wafer

2011 ◽  
Vol 679-680 ◽  
pp. 123-126 ◽  
Author(s):  
Gil Yong Chung ◽  
Mark J. Loboda ◽  
Jie Zhang ◽  
Jian Wei Wan ◽  
E.P. Carlson ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Recent Work ◽  
Basal Plane ◽  
Smooth Surface ◽  
Power Supplies ◽  
Power Device ◽  
Basal Plane Dislocation ◽  
Device Applications ◽  
Photo Voltaic

Improvements in the quality and consistency of 4H-SiC epitaxy wafers are now starting to enable growth of commercial SiC power device applications in areas such as inverters for photo-voltaic systems and power supplies. Recent work has achieved very low epitaxy surface roughness and very low BPD (Basal plane dislocation) in the on 4 degree off-axis substrates. In this paper, we report characterization of the very low BPD epitaxy wafers and a newly observed triangular defect.

Basal Plane Dislocation Conversion Enhancement in 4H-SiC Homo-Epitaxial Layers by Ion Implantation into the Wafer

2019 ◽  
Vol 963 ◽  
pp. 114-118
Author(s):  
Christian Heidorn ◽  
Romain Esteve ◽  
Tobias Höchbauer ◽  
Michael Krieger ◽  
Heiko B. Weber ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Basal Plane ◽  
Defect Density ◽  
Layer Growth ◽  
Growth Defect ◽  
Density Measurements ◽  
Enhancing Effect ◽  
Wafer Substrate ◽  
Basal Plane Dislocation ◽  
The Impact

We studied the impact of ion implantation into the wafer substrate prior to the epitaxy process on the basal plane dislocation conversion behavior during epitaxial layer growth. Defect density measurements show an enhancing effect of the ion implantation on the basal plane dislocation to threading edge dislocation conversion. Analysis of the lateral conversion distribution, the stress field in the material as well as the wafer topography at the onset of epitaxial growth lead us to believe, that stresses in the epitaxy layer cause the enhanced basal plane dislocation conversion.

The stability of dislocation networks under various oxygen-doping conditions in superconducting Bi2Sr2CaCu2Oy single crystals and their influence on the flux pinning properties

1994 ◽  
Vol 52 ◽  
pp. 802-803
Author(s):  
Y. Feng ◽  
X. Y. Cai ◽  
R. J. Kelley ◽  
D. C. Larbalestier
Keyword(s):  
Single Crystals ◽  
Oxygen Content ◽  
Basal Plane ◽  
Flux Pinning ◽  
Pinning Centers ◽  
Before And After ◽  
Anomalous Peak ◽  
Basal Plane Dislocation ◽  
The Stability ◽  
Further Development

The issue of strong flux pinning is crucial to the further development of high critical current density Bi-Sr-Ca-Cu-O (BSCCO) superconductors in conductor-like applications, yet the pinning mechanisms are still much debated. Anomalous peaks in the M-H (magnetization vs. magnetic field) loops are commonly observed in Bi2Sr2CaCu2Oy (Bi-2212) single crystals. Oxygen vacancies may be effective flux pinning centers in BSCCO, as has been found in YBCO. However, it has also been proposed that basal-plane dislocation networks also act as effective pinning centers. Yang et al. proposed that the characteristic scale of the basal-plane dislocation networksmay strongly depend on oxygen content and the anomalous peak in the M-H loop at ˜20-30K may be due tothe flux pinning of decoupled two-dimensional pancake vortices by the dislocation networks. In light of this, we have performed an insitu observation on the dislocation networks precisely at the same region before and after annealing in air, vacuumand oxygen, in order to verify whether the dislocation networks change with varying oxygen content Inall cases, we have not found any noticeable changes in dislocation structure, regardless of the drastic changes in Tc and the anomalous magnetization. Therefore, it does not appear that the anomalous peak in the M-H loops is controlled by the basal-plane dislocation networks.

Sign in / Sign up

Export Citation Format

Share Document